What was found
AT 200 FT AGL ON LANDING GOT CABIN SMOKE LEVEL 3 ALERT, WENT OUT SHORTLY. ALERT ON DURING LANDING ROLL THEN WENT OUT. EMERGENCY DECLARED. ON TAXI, CABIN SMOKE LEVEL 3 ALERT, STEADY. APU RUNNING, ENGINE SHUTDOWN. F/O WENT BACK TO OPEN DOOR, SMELLED SMOKE. EMERGENCY EVACUATION DECLARED. APU FIRE HANDLE PULLED. AGENT WAS DISCHARGED. EXITED BY L-1 ENTRY DOOR SLIDE. R&R CARGO COMPT AFT CARGO DET 5 PER MM 26-14-01-4, DUE FAIL ON TEST & SENT MESSAGE ALERT. R&R NR 2 FIREX ENG/APU CONTAINER PER MM 26-21-01-4. R&R MSC PER MD-11 MM 31-42-01-4 & OPS TEST PER MD-11 MM 31-42-01-5 FOR PRECAUTIONARY PURPOSE. R&R NR 1, 2 & 3 WATER SEPARATOR COALESCER PER MD-11 AMM 21-54-05-2.